1. Technical Field
The present invention relates to thin film transistors and, particularly, to a carbon nanotube based thin film transistor.
2. Description of Related Art
A typical thin film transistor (TFT) is made of a substrate, a gate electrode, an insulation layer, a drain electrode, a source electrode, and a semiconductor layer. The thin film transistor performs a switching operation by modulating an amount of carriers accumulated in an interface between the insulation layer and the semiconductor layer from an accumulation state to a depletion state, with applied voltage to the gate electrode, to change an amount of the current passing between the drain electrode and the source electrode.
Material of semiconductor layer is semiconductive material and materials of source electrode and drain electrode are metal materials. Because materials of source electrode and drain electrode are different from material of semiconductor layer, interface barrier existed between the semiconductor layer and the source electrode or the drain electrode has an adversely effect to the property of thin film transistor. Furthermore, the thickness of the semiconductor layer, the source electrode and the drain electrode is relatively large which affects the light transmittance of the thin film transistor.
What is needed, therefore, is a thin film transistor that can overcome the above-described shortcomings.